The present invention relates to a passenger conveyor control apparatus such that the operating situations of various kinds of safety devices in the passenger conveyor can be employed without comprising the safety of passengers, and can communicate or send information on the actuation of any of the safety devices to a remote centralized monitoring office.
A passenger conveyor, such as escalator or motordriven road, is equipped with various kinds of safety devices including a skirt guard switch, a terminal inlet switch and a chain safety switch. These safety devices are explained in the Japanese Laid-open Patent Publication No. 55-11402/1980 entitled "Passenger Conveyor Safety Apparatus", and also a method for detecting if any of the safety devices has been actuated is explained in detail.
Additionally, a technique is disclosed in the Japanese Laid-open Patent Publication No. 53-61889/1978 entitled "Safety Apparatus for Man Conveyor".
Disclosed in this publication is a system which has the object of reliably stopping the passenger conveyor and ensuring the safety of passengers when any of the safety devices has been actuated; the current of the coil of an electromagnetic switch for driving an electric motor is directly cut off to stop the passenger conveyor by the actuation of the safety device in an arrangement in which the normally-closed contacts of the various safety devices are connected in series with the coil; and which the various safety devices having been actuated is known by the actuation of the safety device from a relay having a self-holding circuit which is turned "on" by the normally-open contact of the actuated safety device of the automatic reset type.
Since, however, the normally-closed contacts of the safety devices are connected in series; this system has the disadvantage that the actuated safety device cannot be identified in a case where two of the safety devices have been simultaneously actuated, such a case of a momentary actuation state where the normally-closed contact has opened, but the normally-open contact has not closed, that is, where the electromagnetic switch has been turned "off" to stop the passenger conveyor, but the self-holding relay cannot self-hold, or a case where the normally-closed contact has bounded and separated due to, for example, the vibrations of a machine constructing, so that only the current of the coil of the electromagnetic switch has been cut off to stop the passenger conveyor.
Therefore, the former technique in the Japanese Laid-open Patent Publication No. 55-11402/1980 adopts a construction wherein the signals of the various safety devices are input to a microcomputer, which is one of digital electronic computers, in parallel, thereby making it possible to distinctively detect even the simultaneous actuations of the safety devices, and wherein the momentary actuation attributally, for example, the mechanical vibrations is not acknowledged as the actuation of the safety device, thereby to prevent the wasteful stops of the passenger conveyor. A disadvantage of this construction, however, is that, when the microcomputer has broken down, the detection of the actuation of any safety device is not fulfilled, so that the escalator cannot be stopped so that the safety devices which has been actuated is not known at the breakdown of the microcomputer, and so on.
Besides it has recently been recognized that a system having a safety device of a manual reset type in which an expert repair person stationed at a centralized monitoring office in a remote place is automatically called out by using a public circuit or the like, is required to resume the safety device promptly.
A similar technique is practised in elevators. This technique has an object to quickly rescue passengers when they have been trapped in the cage of the elevator, and this object differs from that of the technique of the passenger conveyor. More specifically, even when the passenger conveyor has stopped, no person is confined therein, in contrast to the case of the elevator. Since, however, the passenger conveyor is used at a traffic facilities; the prompt resumption is intended as described above.
By the way, examples of such techniques in elevators are "Apparatus for Automatically Reporting Trouble of Elevator" in the Japanese Laid-open Patent Publication No. 48-18942/1973 and "Emergency Reporting Apparatus" in the Japanese Laid-open Patent Publication No. 61-169464/1986.
In a case where, using the prior-art techniques, priority is given to reliably stopping the passenger conveyor upon the actuation of any safety device; the normally-closed contacts of the various safety devices and the coil of the electromagnetic switch may be connected in series. Using this technique, however, there arises the disadvantage that the exact operating situations of the individual safety devices cannot be known.
On the other hand, with the construction wherein the exact operating situations of the individual safety devices are known and wherein priority is given to avoiding the stops caused by trial actuations, the signals of the contacts of the safety devices may be respectively input to the microcomputer. In this case, however, there arise the problem that, when the microcomputer has broken down, the passenger conveyor becomes unsafe because it cannot be stopped by the actuation of any safety device, and the problem arises that the actuated safety device cannot be specified.
Incidentally, when stopping the passenger conveyor such that the breakdown of the microcomputer is detected by a breakdown detector, for example, a so-called watchdog timer, the passenger conveyor is stopped irrespective of the actuation of any safety device, and hence, the passengers will be kept safe. Since, however, the passenger conveyor is a vehicle which is run in a horizontal direction or in a slant direction while carrying the persons thereon, the sudden stop may possibly hurt the passengers due to a falling-dominoes effect. Especially, when the escalator stops during the running down thereof, the possibility is very high of the falling-dominoes effect. Accordingly, the passenger conveyor is inevitably stopped by the actuation of any of emergency devices such as the safety devices for protecting the passengers, but the another stop thereof due to the breakdown of the microcomputer must be avoided.
Also, there is the problem that, when any of the manual type safety devices has been actuated, the actuation is to be immediately communicated (sent as a message) to the repair person stationed at the centralized monitoring office in the remote place, so as to repair the safety device promptly.